So, in your view, Ukraine cannot decide what to do because else Putin would not feel "secure" despite having a nuclear arsenal? Just think of it in in the opposite way: "Russian should demilitarise so that Ukraine feels secure". You see how absurd that is?
I'm not saying that we're living in a perfect world...but seeing USA/NATO track record since WW2, can you blame Russians?
Looking at Napoleon, Hitler, Genghis Khan and numerous other invasions, can you blame Russians?
I suggest you look for and watch Oliver Stone (lenghty) interview with Putin on Youtube
hell, USA was afraid of small Grenada and attacked state of 100 thousands people with almost no military
What you are doing is saying that Ukraine acted "as if" they wanted to be invaded.